This project takes advantage of a 'natural experiment' occurring in Alabama and Georgia, states which have many similarities but which have taken different approaches to providing health insurance coverage for low income children. This project examines 1) changes in provider availability across communities in the two states and 2) changes over time and differences across plans in children's utilization of appropriate care. Provider availability is examined with longitudinal panel studies of claims data covering two periods, the introduction of pccm into the Medicaid programs and the expansion of the number of children covered by CHIP programs. Zip codes are the unit of analysis, and the number of participating providers in both plans, the extent of their participation and the concentration of patients across providers are the measures of provider availability. A longitudinal panel study of claims generated by Medicaid enrolled children will be used to examine the impact of primary care case management and provider availability, on several measures of access to care. Three annual cross sectional studies of Medicaid and CHIP enrollees during 1999-2001 will examine the impact of provider availability and insurance plan features on access measures. Both studies of children will include sub-studies of African American children (about 50 percent of the enrollees in both states) and of children with special health care needs (as identified by diagnoses and eligibility categories). These studies will be complemented by enrollee surveys of the Medicaid and CHIP enrollees in the two states to examine perceived ease of access to and quality of care. In addition, providers, CHIP and Medicaid enrollees in six varied communities in each state will participate in focus groups exploring the impact of insurance coverage and other delivery system factors on use and provision of health care to low income children.